NOMAD: Non-locking, stOchastic Multi-machine algorithm for Asynchronous and Decentralized matrix completion

We develop an efficient parallel distributed algorithm for matrix completion, named NOMAD (Non-locking, stOchastic Multi-machine algorithm for Asynchronous and Decentralized matrix completion). NOMAD is a decentralized algorithm with non-blocking communication between processors. One of the key features of NOMAD is that the ownership of a variable is asynchronously transferred between processors in a decentralized fashion. As a consequence it is a lock-free parallel algorithm. In spite of being an asynchronous algorithm, the variable updates of NOMAD are serializable, that is, there is an equivalent update ordering in a serial implementation. NOMAD outperforms synchronous algorithms which require explicit bulk synchronization after every iteration: our extensive empirical evaluation shows that not only does our algorithm perform well in distributed setting on commodity hardware, but also outperforms state-of-the-art algorithms on a HPC cluster both in multi-core and distributed memory settings

Clinical Research Environment in India: Challenges and Proposed Solutions.

India has compelling need and keen aspirations for indigenous clinical research. Notwithstanding this need and previously reported growth the expected expansion of Indian clinical research has not materialized. We reviewed the scientific literature, lay press reports, and ClinicalTrials.gov data for information and commentary on projections, progress, and impediments associated with clinical trials in India. We also propose targeted solutions to identified challenges. The Indian clinical trial sector grew by (+) 20.3% CAGR (compound annual growth rate) between 2005 and 2010 and contracted by (-) 14.6% CAGR between 2010 and 2013. Phase-1 trials grew by (+) 43.5% CAGR from 2005-2013, phase-2 trials grew by (+) 19.8% CAGR from 2005-2009 and contracted by (-) 12.6% CAGR from 2009-2013, and phase-3 trials grew by (+) 13.0% CAGR from 2005-2010 and contracted by (-) 28.8% CAGR from 2010-2013. This was associated with a slowing of the regulatory approval process, increased media coverage and activist engagement, and accelerated development of regulatory guidelines and recuperative initiatives. We propose the following as potential targets for restorative interventions: Regulatory overhaul (leadership and enforcement of regulations, resolution of ambiguity in regulations, staffing, training, guidelines, and ethical principles [e.g., compensation]).Education and training of research professionals, clinicians, and regulators.Public awareness and empowerment. After a peak in 2009-2010, the clinical research sector in India appears to be experiencing a contraction. There are indications of challenges in regulatory enforcement of guidelines; training of clinical research professionals; and awareness, participation, partnership, and the general image amongst the non-professional media and public. Preventative and corrective principles and interventions are outlined with the goal of realizing the clinical research potential in India

Studies on Macronutrient Fertilization in Pomegranate under Sub-Tropical Plains

An investigation was carried out to study the influence of different levels of NPK fertilizers on plant growth, fruit yield and quality, and leaf NPK content in pomegranate cv. Kandhari under sub-tropical conditions. Graded doses of nitrogen (0-300g/plant), phosphorus (0-150g/plant) and potassium (0-300g/plant) fertilizers were applied through soil, in addition to a basal dose of FYM. Control plants were fed FYM only. Maximum increase in plant growth and fruit yield was recorded in plants receiving NPK @ 300:50:100g/plant, while Control plants registered least growth and yield. Potassium levels improved fruit weight over the Control. Higher dose of potassium also improved fruit colour and enhanced peel thickness and grain weight. Maximum TSS:acid ratio was seen with NPK @ 200:50:100g/plant. Reducing sugars were not affected by any treatment. Leaf N, P and K content increased with application of the respective nutrient

How explicit are the barriers to failure in safety arguments?

Safety cases embody arguments that demonstrate how safety properties of a system are upheld. Such cases implicitly document the barriers that must exist between hazards and vulnerable components of a system. For safety certification, it is the analysis of these barriers that provide confidence in the safety of the system. The explicit representation of hazard barriers can provide additional insight for the design and evaluation of system safety. They can be identified in a hazard analysis to allow analysts to reflect on particular design choices. Barrier existence in a live system can be mapped to abstract barrier representations to provide both verification of barrier existence and a basis for quantitative measures between the predicted barrier behaviour and performance of the actual barrier. This paper explores the first stage of this process, the binding between explicit mitigation arguments in hazard analysis and the barrier concept. Examples from the domains of computer-assisted detection in mammography and free route airspace feasibility are examined and the implications for system certification are considered

X-Ray and Infrared Enhancement of Anomalous X-ray Pulsar 1E 2259+58

The long term (~1.5 years) X-ray enhancement and the accompanying infrared enhancement light curves of the anomalous X-ray pulsar 1E 2259+58 following the major bursting epoch can be accounted for by the relaxation of a fall back disk that has been pushed back by a gamma-ray flare. The required burst energy estimated from the results of our model fits is low enough for such a burst to have remained below the detection limits. We find that an irradiated disk model with a low irradiation efficiency is in good agreement with both X-ray and infrared data. Non-irradiated disk models also give a good fit to the X-ray light curve, but are not consistent with the infrared data for the first week of the enhancement.Comment: 17 pages, 3 figures, accepted for publication in Ap

Overestimation of Vitamin a Supplementation Coverage from District Tally Sheets Demonstrates Importance of Population-Based Surveys for Program Improvement: Lessons from Tanzania.

Tanzania has conducted a national twice-yearly Vitamin A supplementation (VAS) campaign since 2001. Administrative coverage rates based on tally sheets consistently report >90% coverage; however the accuracy of these rates are uncertain due to potential errors in tally sheets and their aggregation, incomplete or inaccurate reporting from distribution sites, and underestimating the target population. The post event coverage survey in Mainland Tanzania sought to validate tally-sheet based national coverage estimates of VAS and deworming for the June 2010 mass distribution round, and to characterize children missed by the national campaign. WHO/EPI randomized cross-sectional cluster sampling methodology was adapted for this study, using 30 clusters by 40 individuals (n = 1200), in addition to key informant interviews. Households with children 6-59 months of age were included in the study (12-59 months for deworming analysis). Chi-squared tests and logistic regression analysis were used to test differences between children reached and not reached by VAS. Data was collected within six weeks of the June 2010 round. A total of 1203 children, 58 health workers, 30 village leaders and 45 community health workers were sampled. Preschool VAS coverage was 65% (95% CI: 62.7-68.1), approximately 30% lower than tally-sheet coverage estimates. Factors associated with not receiving VAS were urban residence [OR = 3.31; p = 0.01], caretakers who did not hear about the campaign [OR = 48.7; p<0.001], and Muslim households [OR<3.25; p<0.01]. There were no significant differences in VAS coverage by child sex or age, or maternal age or education. Coverage estimation for vitamin A supplementation programs is one of most powerful indicators of program success. National VAS coverage based on a tally-sheet system overestimated VAS coverage by ∼30%. There is a need for representative population-based coverage surveys to complement and validate tally-sheet estimates

Temporal artery biopsies in south-east Scotland:a five year review

Temporal artery biopsy is the gold standard investigation for the diagnosis of giant cell arteritis. The aim of this retrospective study was to investigate the use of temporal artery biopsy in diagnosing giant cell arteritis in south-east Scotland over a five-year period. We aimed to quantify success rates, and predictive factors for a positive biopsy, as well as compare the different specialities performing the biopsies. The data should enable the development of better criteria for referral for investigation of giant cell arteritis. Methods Patients were identified using a database of temporal artery biopsies generated by the pathology department in NHS Lothian (south east Scotland), for all biopsies examined between January 2010 and December 2015. An electronic patient record was used to retrospectively examine the records of patients in the database. Results A total of 715 biopsies were included in the study, of which 250 (35.0%) showed features of giant cell arteritis. The main predictors for a positive biopsy were age at biopsy, specialty performing biopsy, erythrocyte sedimentation rate, jaw claudication/pain, and ophthalmic symptoms. The most important predictor of a positive biopsy was erythrocyte sedimentation rate. The length of biopsy was not found to be a predictor of positive biopsy; however, diameter of biopsy was predictive. Conclusions We have shown that many temporal artery biopsies are negative, and finding ways to reduce the number of patients unnecessarily undergoing biopsy will be essential in reducing workload and streamlining services. This study demonstrates some key predictive factors for patients with positive biopsies. The study also shows that a large proportion of biopsies taking place do not result in the recommended length of specimen, but this does not necessarily reduce the likelihood of a positive biopsy

Observations of the SW Sextantis star DW Ursae Majoris with the Far Ultraviolet Spectroscopic Explorer

We present an analysis of the first far-ultraviolet observations of the SW Sextantis-type cataclysmic variable DW Ursae Majoris, obtained in November 2001 with the Far Ultraviolet Spectroscopic Explorer. The time-averaged spectrum of DW UMa shows a rich assortment of emission lines (plus some contamination from interstellar absorption lines including molecular hydrogen). Accretion disk model spectra do not provide an adequate fit to the far-ultraviolet spectrum of DW UMa. We constructed a light curve by summing far-ultraviolet spectra extracted in 60-sec bins; this shows a modulation on the orbital period, with a maximum near photometric phase 0.93 and a minimum half an orbit later. No other periodic variability was found in the light curve data. We also extracted spectra in bins spanning 0.1 in orbital phase; these show substantial variation in the profile shapes and velocity shifts of the emission lines during an orbital cycle of DW UMa. Finally, we discuss possible physical models that can qualitatively account for the observed far-ultraviolet behavior of DW UMa, in the context of recent observational evidence for the presence of a self-occulting disk in DW UMa and the possibility that the SW Sex stars may be the intermediate polars with the highest mass transfer rates and/or weakest magnetic fields.Comment: accepted by the Astronomical Journal; 36 pages, including 12 figures and 4 table

The magnetar emission in the IR band: the role of magnetospheric currents

There is a general consensus about the fact that the magnetar scenario provides a convincing explanation for several of the observed properties of the Anomalous X-ray Pulsars and the Soft Gamma Repeaters. However, the origin of the emission observed at low energies is still an open issue. We present a quantitative model for the emission in the optical/infrared band produced by curvature radiation from magnetospheric charges, and compare results with current magnetars observations.Comment: 6 Pages, 2 Figures. Astrophysics and Space Science, in press. Proceedings of the ICREA Workshop on The High-Energy Emission from Pulsars and their Systems, Sant Cugat, April 12-16 201